You can confirm the DSN that is in use by checking the registry: HKLM\Software\VMware\VMware, Inc.\VMware Update Manager\DB: The login, DSN name and client type are all listed. Assuming you used a separate DSN from vCenter, this should help you verify.
If you need to verify the DSN then you can check: HKLM\SOFTWARE\ODBC\ODBC.INI\<your DSN name here>. The "Database" string value has the name of the SQL database that is the target of the DSN.
Dennis